1. Field of the Invention
The present invention is related to a stereoscopic display device, and particularly, to a stereoscopic display device having sub-pixels designed for improving chromatic homogeneity.
2. Description of the Prior Art
Stereoscopic display technique provides two separate images individually to the left and right eyes of an observer. When the brain of the observer overlaps and analyzes those separate images, different depths and gradations of each component are perceived, and thus the observer obtains stereoscopic vision. Please refer to FIG. 1, which is a schematic drawing illustrating the stereoscopic display technique. As shown in FIG. 1, a conventional stereoscopic liquid crystal display (LCD) device 100 includes a backlight module 110, an LCD panel 120, and a parallax device 130. The backlight module 110 is positioned at a back-side of the LCD panel 120 for providing lights while the parallax device 130 is positioned at a front-side of the LCD panel 120 for dividing the image signals of the LCD panel 120. When images are shown by the stereoscopic LCD display device 100, those images are separated by the parallax device 130 and respectively captured by the left eye L or right eye R of the observer due to different view angles of the left eye L and right eye R.
Please refer to FIG. 2, which is a conventional sub-pixel design of the stereoscopic LCD panel 120. As shown in FIG. 2, the conventional stereoscopic LCD panel 120 includes a plurality of sub-pixels 122R, 122G, 122B that individually provides red, green, or blue signals. And the sub-pixels 122R, 122G, 122B are arranged in strips as shown in FIG. 2. The stereoscopic LCD panel 120 further includes a parallax device 130 having an oblique-stripe parallax pattern. Through a plurality of transparent regions 132 of the parallax device 130, single left or right eye of the observer obtains images mixed by the sub-pixels. Those skilled in the art would easily realize that only one transparent region is shown in FIG. 2 for clarity. However, since the pixel are constructed by three sub-pixels 122R, 122G, 122B that are obliquely parallel to each other, it is often found that mixture of the sub-pixels is not good enough according to the conventional sub-pixel design.
In order to avoid the abovementioned disadvantage, other sub-pixel design is developed. Please refer to FIG. 3, which is a schematic drawing of a sub-pixel design formed on the LCD panel 120 according to U.S. Patent Application Publication No.: US 2007/0058113, and an image for a single eye through the parallax device 130. According to US 2007/0058113, a plurality of sub-pixels units respectively possessing sub-pixels 124R, 124G, 124B, and a parallax device 130 possessing shielding regions in a grille pattern are provided. Therefore the obtained pixel images include the sub-pixels 124R, 124G, 124B that are arranged in a delta as shown in FIG. 3. According to the sub-pixel design, chromatic homogeneity is expected to be improved. However, the shielding regions 134 of the grille pattern unavoidably shield the sub-pixel 124R, 124G, or 124B of the sub-pixels units. In other words, the shielding region 134 exists in the sub-pixels 124R, 124G, or 124B as shown in FIG. 3. Consequently, distance between the sub-pixels 124R, 124G, 124B of a pixel is increased, and thus chromatic homogeneity and luminance of the stereoscopic display device 100 are deteriorated.
Therefore, a sub-pixel design that is able to improve chromatic homogeneity is needed to further improve image quality and color quality of the stereoscopic display device.